水平荷载下纵截面异形桩承载特性试验

针对纵截面异形桩（扩底桩和楔形桩）、等混凝土用量常规等直径桩的水平向承载特性进行对比模型试验研究，测得不同水平荷载等级下扩底桩和楔形桩的内力、变形、极限承载力和桩侧土压力分布等变化规律特性；初步探讨3种桩型的水平极限承载特性和桩侧土压力分布规律。考虑纵向截面异形效应，基于水平土抗力与水平位移（p-y）曲线法建立纵截面异形桩水平向承载特性理论计算方法，进一步分析弯矩分布规律，并开展影响因素分析。研究结果表明，在当前试验条件下，等混凝土用量楔形桩的水平向承载力比等直径桩的高，砂性土和黏性土中楔形桩水平向极限承载力约分别为等直径桩的1.25倍和1.33倍。相关研究成果可为今后类似土层下水平受荷纵截面异形桩的设计与计算提供参考依据。

Model tests on bearing capacity of longitudinal section shaped pile under lateral load

A series of model tests was conducted to compare the horizontal bearing capacities of longitudinal section shaped pile (belled pile and tapered pile), and traditional equal-diameter pile, which have identical volume of concrete. The distribution of the internal force and deformation of piles, the ultimate bearing capacity, and lateral soil pressure were measured under different levels of horizontal load. The distribution of the ultimate bearing capacity and lateral soil pressure of three different pile types were comparatively analyzed. A theoretical method was developed to calculate the lateral bearing capacity of longitudinal section shaped pile based on p-y curve method and by considering shape effect. The distribution of pile moments and influencing factors were discussed. The results show that the horizontal bearing capacity of tapered pile is larger than those of belled pile and equal-diameter pile with identical volume of concrete. The ultimate horizontal bearing capacity of tapered pile embedded in sand and clay is nearly 1.25 times and 1.33 times of that of equal-diameter pile. These experimental results are useful for practical engineering and analysis of longitudinal section shaped piles in different applications.